CLHS: Function PPRINT-INDENT

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Function PPRINT-INDENT

Syntax:

pprint-indent relative-to n `&optional` stream => nil

Arguments and Values:

relative-to---either `:block` or `:current`.

n---a real.

stream---an output stream designator. The default is standard output.

Description:

pprint-indent specifies the indentation to use in a logical block on stream. If stream is a pretty printing stream and the value of *print-pretty* is true, pprint-indent sets the indentation in the innermost dynamically enclosing logical block; otherwise, pprint-indent has no effect.

N specifies the indentation in ems. If relative-to is `:block`, the indentation is set to the horizontal position of the first character in the dynamically current logical block plus n ems. If relative-to is `:current`, the indentation is set to the current output position plus n ems. (For robustness in the face of variable-width fonts, it is advisable to use `:current` with an n of zero whenever possible.)

N can be negative; however, the total indentation cannot be moved left of the beginning of the line or left of the end of the rightmost per-line prefix---an attempt to move beyond one of these limits is treated the same as an attempt to move to that limit. Changes in indentation caused by pprint-indent do not take effect until after the next line break. In addition, in miser mode all calls to pprint-indent are ignored, forcing the lines corresponding to the logical block to line up under the first character in the block.

Examples: None.

Side Effects: None.

Affected By: None.

Exceptional Situations:

An error is signaled if relative-to is any object other than `:block` or `:current`.

See Also:

Section 22.3.5.3 (Tilde I: Indent)

Notes: None.

The following X3J13 cleanup issues, not part of the specification, apply to this section:

- GENERALIZE-PRETTY-PRINTER:UNIFY
- PRETTY-PRINT-INTERFACE

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